Observations on the significance of diagnostic findings in egg-binding of Psittaciformes

Egg binding in the parrot family

source: M-E. Krautwald-Junghanns, V.M. Kostka and H. Hofbauer
Veterinary Record (1998) 143
starts p498, 5 pages long

A survey of 2,192 Psittaciformes has found 60 birds, (2.74% of the sample) cases of egg binding. The parrot family is not easy to sex, so the sample included males, estimated at around half the total. Egg binding is especially common in cockatiels, at 15.75% or 20 birds of 127, and budgerigars, at 5.37%, or 19 birds of 354, in this sample. It is rare in some parrot species, eg the Amazona species at 0.18% (one bird of 555), and Psittacus species (including African Grey parrots), at 0.22% (one bird of 464). Rates for the Ara species (including blue and yellow macaws) were 4.7% (seven birds of 149), and for Cacatua species (including sulphur crested cockatoos) were 2% (3 birds of 149).

Egg binding can be linked to malnutrition. Vitamin D, vitamin E, selenium and calcium supplies are important for successful breeding. Stress may be a contributory factor, eg long daylight hours, low humidity, an unsuitable temperature range, and social stress, from a new bird partner, or from humans, may also contribute. Egg binding may also be directly caused by weak or absent tonus of cloacal musculature or the oviduct, large eggs, eggs with soft or no shells, or rough surfaces, and adhesions affecting the oviduct and eggshell.

Affected birds are more likely to be caged than in an aviary, but being paired or single appears to make no difference. Birds are more likely to suffer from egg binding if they have never bred before. Four of the sample had previously bred, though 32 of the others had previously laid eggs, and 24 were laying for the first time. Seasonal factors do not appear to be important. Reproductive tract disease was evident in 36 cases.

Symptoms included a swollen abdomen in all cases, with 36 of the birds having problems with defecation. Other symptoms can include being unable to fly, and standing in a wide-legged way.

A diagnosis was possible in 70% of cases just by looking at the bird, taking the bird’s history, and palpating its abdomen. Radiography helped in diagnosing birds with eggs deep inside the bird, but eggs with thin or no shells could not be reliably diagnosed either by palpation or radiography. Radiography was also little help in diagnosing eggs with laminated shells. Ultrasonic examination helped in diagnosing eggs with defective and thin shells, but roughness of egg shells was not easily observable using ultrasound.